> For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://docs.proto.xyz/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.proto.xyz/_mcp/server. # Install a high-availability cluster Install Proto Fleet high availability (HA) on three dedicated Linux hosts. You run one command for each host. The installer creates the cluster configuration and credentials. ## Before you begin Confirm that you have: * Three [supported hosts](/fleet/high-availability#supported-hosts) on the same local network * Reserved IPv4 addresses for `ha-a`, `ha-b`, and `ha-c` * An unused IPv4 address for the virtual IP, excluded from the DHCP pool * The same SSH username on `ha-b` and `ha-c` * SSH and `sudo` access to every host * `curl` on every host * Outbound HTTPS access to GitHub releases and the host package repositories The hosts can use different processor architectures. The installer selects the correct release artifact for each host and pins all three hosts to the same Proto Fleet version. #### Start the installation on ha-a From your operator machine, run the public installer on `ha-a`. Replace the SSH destination with the username and address for your host: ```bash ssh -A -t admin@10.40.0.11 'curl -fsSL https://fleet.proto.xyz/install.sh | sudo --preserve-env=SSH_AUTH_SOCK bash -s -- --ha' ``` The `-A` option forwards your SSH agent to `ha-a`, and `--preserve-env=SSH_AUTH_SOCK` keeps it available to the installer when it connects to the peers. If you use passwords instead, omit both options and respond to the prompts. The installer downloads the correct release artifact and verifies its checksum. It then asks for: 1. The `ha-b` IPv4 address 2. The `ha-c` IPv4 address 3. The virtual IPv4 address 4. The SSH username shared by `ha-b` and `ha-c` Review the displayed topology and host changes. Type `INSTALL` to continue. The installer checks both SSH destinations before it changes `ha-a`. It then sends each peer its protected host bundle and installs the local HA service. Password and host-key prompts can appear during the SSH checks. When `ha-a` finishes, save the public service CA fingerprint and the complete commands for `ha-b` and `ha-c` from its output. #### Install ha-b On your operator machine, run the first command printed by `ha-a`. The command confirms that the prepared bundle is present. It then downloads and verifies the release selected by `ha-a` and installs the full passive Fleet host. You do not transfer a release archive or confirm the installation again. The command returns after the local HA service starts. The cluster continues to converge in the background while `ha-c` joins. #### Install ha-c On your operator machine, run the second command printed by `ha-a`. The witness downloads and verifies the same release, installs the coordination service, and waits until Fleet is active through the virtual IP. If it continues waiting after the other two commands finish, see [installation remains at peer waiting](/fleet/high-availability/troubleshooting#installation-remains-at-peer-waiting). When the virtual IP is ready, the command prints the public service CA download and fingerprint commands. #### Verify and trust the public service CA Run the CA commands printed by `ha-c` on your operator machine. They: 1. Download the public certificate from the virtual IP. 2. Write one parsed certificate to `proto-fleet-ha-service-ca.crt`. 3. Display its SHA-256 fingerprint. Compare that fingerprint with the value printed in the authenticated `ha-a` session. Import `proto-fleet-ha-service-ca.crt` only when the values match. Do not import the certificate before comparing the fingerprints. Never import or distribute a host bundle. Host bundles contain private keys and cluster credentials. #### Trust the certificate on a Debian-based client ```bash sudo install -m 0644 proto-fleet-ha-service-ca.crt /usr/local/share/ca-certificates/proto-fleet-ha-service-ca.crt sudo update-ca-certificates ``` Other operating systems and managed browsers have their own trust-store settings. #### Open Fleet Open `https://` in a browser that trusts the public service CA. Create the administrator account and pair miners through the normal first-run flow. If the installer stops or Fleet does not open at the virtual IP, see [HA troubleshooting](/fleet/high-availability/troubleshooting).